Substrate holder and plating apparatus

ABSTRACT

The present invention is to provide a substrate holder which can effect a more complete sealing with a sealing member and makes it possible to take a substrate out of the substrate holder easily and securely, and also a plating apparatus provided with the substrate holder. The substrate holder includes: a fixed holding member and a movable holding member for holding a substrate therebetween; a sealing member mounted to the fixed holding member or the movable holding member; and a suction pad for attracting a back surface of the substrate held between the fixed holding member and the movable holding member.

This application is a divisional of U.S. application Ser. No.10/482,476, filed Aug. 19, 2004 now U.S. Pat. No. 7,601,248, which is anational stage application of International application No.PCT/JP2003/07855, filed Jun. 20, 2003.

TECHNICAL FIELD

The present invention relates to a substrate holder for use in a platingapparatus for plating a to-be-plated surface of a substrate, especiallya plating apparatus for forming a plated film in fine interconnecttrenches or holes, or resist openings provided in a surface of asemiconductor wafer, or for forming bumps (protruding electrodes), whichare to be electrically connected to electrodes, or the like, of apackage, on a surface of a semiconductor wafer, and also to a platingapparatus provided with the substrate holder.

BACKGROUND ART

In tape automated bonding (TAB) or flip chip bonding, for example, ithas been widely conducted to deposit gold, copper, solder, nickel ormulti-layered materials thereof at prescribed areas (electrodes) on asurface of a semiconductor chip having interconnects, thereby formingprotruding connecting electrodes (bumps). Such bumps electricallyconnect the semiconductor chip with package electrodes or TABelectrodes. There are various methods for forming these bumps, includingan electroplating method, vapor deposition method, printing method, andball bump method. The electroplating method has become in wide use dueto its relatively stable performance and capability of forming fineconnections, in view of a recent tendency to increasing number of I/Oterminals on semiconductor chips and to finer pitch.

The electroplating method includes a spurting or cup method in which asubstrate such as a semiconductor wafer is positioned horizontally witha processing surface to be plated facing downward and a plating solutionis spurted from below; and a dipping method in which the substrate isplaced vertically in a plating tank and immersed in a plating solution,while a plating solution is supplied from a bottom of the plating tankand is allowed to overflow the tank. According to the dipping method ofelectroplating, bubbles that can adversely affect quality of plating areeasily removed and a footprint is small. The dipping method is thereforeconsidered to be suited for bump plating in which holes to be filled bythe plating are relatively large and which requires a fairly longplating time.

Conventional electroplating apparatuses, employing the dipping method,are provided with a substrate holder which detachably holds a substrate,such as a semiconductor wafer, with its end and back surfaces sealedwhile its front surface (to-be-plated surface) is exposed. Suchconventional apparatuses perform plating of the surface of the substrateby dipping the substrate holder, together with the substrate held by it,in a plating solution, and have an advantage of easy release of gasbubbles.

Since a substrate holder with a substrate held is dipped in a platingsolution, the substrate holder is required to securely seal a peripheralportion of the substrate so that the plating solution will not intrudeinto a back surface (non-plating surface) side. Accordingly, in asubstrate holder which detachably holds a substrate between a pair ofsupports (holding members), for example, a sealing member is mounted toone support and the sealing member is brought into pressure contact witha peripheral portion of the substrate placed and held on the othersupport, thereby sealing a peripheral portion of the substrate.

With reference to such a conventional substrate holder, attempts havebeen made to avoid leakage of a plating solution or other liquid, as byoptimization of a shape, fixing method, and the like of the sealingmember, periodical (including per substrate) cleaning of the sealingmember, periodical change of the sealing member, improvement ofprecision in pretreatments of a substrate (formation of a seed layer ora photo resist film), or minimization of error in setting of a substratein the substrate holder as well as periodical realignment.

Due to deterioration of the sealing member, however, it is difficult toeffect a complete sealing. Complete sealing is difficult especially inperforming plating to embed a plated film into fine recesses, since aplating solution having a good permeability is generally used in such aplating so that the plating solution can easily and fully permeate intothe fine recesses. On the other hand, it is also generally difficult todetect leakage of plating solution or other liquid. Once leakage ofplating solution occurs, the plating solution, which has leaked into asubstrate holder, adheres to a back surface of a substrate, and theplating solution adhering to the substrate will transfer to a substratetransport device, resulting in staining of the entire apparatus with theplating solution. In addition, leaked plating solution can corrode anelectrical contact, thereby preventing feeding of electricity.

When performing electroplating of a substrate held by a substrateholder, it is necessary to electrically connect the substrate to anegative pole of a power source. Accordingly, positioned e.g. inside asealing member and in a region sealed with the sealing member, there isprovided an electrical contact for electrically connecting the substrateto an external wire extending from a power source.

A known such electrical contact includes a metal contact plate of e.g.stainless steal having a horseshoe-shape cross-section, and a coilspring for biasing the metal contact plate toward a substrate. When thesubstrate is held by the substrate holder, one leg of the metal contactplate positioned on an outer side contacts an external wire throughelastic force of the coil spring, while another leg of the metal contactplate positioned on an inner side contacts the substrate.

With a substrate holder having such an electrical contact, since themetal contact plate constituting the electrical contact is generally ofa rigid body, the contact plate makes point contact with a substrate,and therefore, poor contact is likely to occur. Further, the metalcontact plate contacts the substrate at a position somewhat inside aperiphery of the substrate, which narrows an effective area for patternformation in the substrate.

In addition, substrates and members generally vary in size. Due to thissize variation and also to a positional relationship between a pair ofsupports, positioning (centering) of a substrate to be held by thesupports with respect to a sealing member mounted to one of the supportsis generally difficult. A separate provision of a special member forpositioning of a substrate leads to a large-sized and complicatedsubstrate holder.

Furthermore, according to the conventional substrate holder, a sealingmember is mounted to one of a pair of supports and the sealing member isbrought into pressure contact with a peripheral portion of a substrateplaced and held on the other support, thereby sealing the peripheralportion of the substrate, as described above. There is, therefore, acase where when opening the support, to which the sealing member ismounted, to take the substrate out of the substrate holder aftercompletion of plating, the support opens with the substrate sticking tothe sealing member and the substrate falls from the support. Measuresmust therefore be taken to solve this problem.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above situation inthe prior art. It is therefore a first object of the present inventionto provide a substrate holder which can effect a more complete sealingwith a sealing member and makes it possible to take a substrate out ofthe substrate holder easily and securely, and also a plating apparatusprovided with the substrate holder.

It is a second object of the present invention to provide a substrateholder which can broaden an effective area for pattern formation in asubstrate, can easily effect centering of the substrate upon holding ofthe substrate, and makes it possible to take the substrate out of thesubstrate holder easily and securely, and also a plating apparatusprovided with this substrate holder.

In order to achieve the above objects, the present invention provides asubstrate holder, comprising: a fixed holding member and a movableholding member for holding a substrate therebetween; a sealing membermounted to the fixed holding member or the movable holding member; and asuction pad for attracting a back surface of the substrate held betweenthe fixed holding member and the movable holding member.

Since the back surface of the substrate is kept attracted to the suctionpad, when the movable holding member is moved after plating to releaseholding of the substrate and take the substrate out of the substrateholder, the substrate can be prevented from sticking to the sealingmember and moving along with the sealing member. Further, since thesubstrate is thus prevented from being brought upward, when performingan automatic operation using an automatic transport device, thesubstrate can be taken out of the substrate holder stably.

The suction pad preferably includes a cup portion of a flexiblematerial, with an inside space of the cup portion defining adecompression portion, and attracts the substrate by a suction forcewhich is produced when the substrate presses the opening of the cupportion and forces air out of the decompression portion to therebyreduce pressure in the decompression portion.

The suction pad is a so-called suction cup. An attraction force of thesuction pad is set at such a degree that when taking the substrate outof the substrate holder, the substrate can be moved horizontally awayfrom the cup portion so that a vacuum can be broken, the substrate canbe easily separated from the sealing member, and the substrate can betransferred to a transport robot. Thus, the suction pad has a strongadhesion to the substrate in a vertical direction, and therefore iseffective for holding of the substrate, while it allows the substrate tomove horizontally and detach from it easily. In a case where the movablemember is designed to be openable and closable via a hinge, it ispreferred to locate the suction pad on an opposite side of a center ofthe substrate, held between the fixed holding member and the movableholding member, from the hinge and at a position corresponding to aperipheral portion of the substrate. The suction pad at such a locationprevents, when opening the movable holding member via the hinge, thatperipheral portion of the substrate from sticking to the sealing memberand being brought up, which portion would otherwise be first brought up,and can effectively separate the substrate from the sealing member.

The suction pad may be connected to a vacuum, and attracts the substrateby vacuuming through a vacuum line. This makes it possible to attractthe substrate to the suction pad and hold the substrate on it easily andsecurely. This holding of the substrate can be released by stopping thevacuuming.

The present invention provides another substrate holder, comprising: afixed holding member and a movable holding member for holding asubstrate therebetween; and a sealing member, mounted to the movableholding member, for making pressure contact with a peripheral portion ofthe substrate to seal the peripheral portion, wherein the sealing memberis held integrally by a holding member.

Since the sealing member is thus integrally mounted to a holding member,when the movable holding member is moved after plating to releaseholding of the substrate and the substrate is taken out of the substrateholder, the sealing portion of the sealing member can be prevented fromadhering to the substrate, and the sealing member can be prevented frombeing torn off from the holding member. Releasability of the sealingmember from the substrate can thus be improved.

It is preferred to use as the sealing member a multi-seal structurecomprising at least two loop-shaped portions. By sealing a peripheralportion of the substrate with a sealing member comprised of themulti-seal structure, a sealing width is substantially widened, so thata more complete sealing can be attained even when centering of thesubstrate is not perfect.

The multi-seal structure preferably includes partition sealing portionsextending in a width direction and provided at certain locations along acircumferential direction. By sealing certain portions along thecircumferential direction of the sealing member with the partitionsealing portions in the width direction, it becomes possible to maintaina sealing ability of the sealing member even when it is damaged.

The present invention provides yet another substrate holder, comprising:a fixed holding member and a movable holding member for holding asubstrate therebetween; and a sealing member, mounted to the movableholding member, for sealing between the movable holding member and thefixed holding member; wherein the sealing member has a W-shapedcross-section, easily collapses when pressed in a width direction, andrecovers by its own elastic force when a pressing force is released.

Use of such a sealing member can facilitate its insert into a sealgroove, e.g. in a dovetail shape, and prevent it from falling from theseal groove securely. Further in this connection, there is a cut-awayportion formed in the movable holding member, which portion is necessaryfor takeout of a tool upon formation of this dovetail-shaped sealgroove. There is, therefore, a fear that a plating solution wouldintrude from the cut-away portion into the seal groove and, due todenaturing or solidification of the plating solution, a sealing abilityof the sealing member would be lowered. In this regard, according to thesubstrate holder of this embodiment, side surfaces of the sealing memberare in contact with sidewall surfaces of the seal groove with a certainelastic force. This prevents the above-described intrusion of platingsolution, thereby ensuring sealing and enhancing durability of thesealing member.

The present invention provides yet another substrate holder, comprising:a fixed holding member and a movable holding member for holding asubstrate therebetween; a sealing member mounted to the fixed holdingmember or the movable holding member; and a plate-shaped spring memberfor biasing the substrate toward the fixed holding member when releasingholding of the substrate between the movable holding member and thefixed holding member.

By use of the spring member, when the movable member is moved afterplating to release holding of the substrate and take the substrate outof the substrate holder, movement of the substrate is restricted and thesealing member mounted to the movable holding member is detached fromthe substrate, whereby the substrate can be prevented from sticking tothe sealing member and moving along with the sealing member.

The spring member is preferably a laminated leaf spring comprising alaminate of two or more leaf spring-shaped plates. Such a laminated leafspring member can secure a long stroke without a plastic deformation andcan be set in a considerably small space.

The present invention provides yet another substrate holder, comprising:a fixed holding member and a movable holding member for holding asubstrate therebetween; a sealing member mounted to the fixed holdingmember or the movable holding member; and a leaf spring member formaking elastic contact with a peripheral portion of the substrate whenthe substrate is held between the movable holding member and the fixedholding member.

Since the substrate is biased inwardly by an elastic force of the leafspring member, positioning (centering) of the substrate relative to thesubstrate holder upon holding of the substrate by the substrate holdercan be effected by the leaf spring member.

The movable holding member preferably has a function of positioning thesubstrate with respect to the sealing member.

Preferably, the leaf spring member also serves as an electrical contactthat contacts the substrate to feed electricity to the substrate. Thiseliminates a need to separately provide the electrical contact, thussimplifying structure of the substrate holder.

The movable holding member preferably has a function of positioning thesubstrate with respect to the sealing member and the electrical contact.

By thus providing the movable holding member with the substrate-sealingmember and preferably the electrical contact for feeding electricity tothe substrate, and also a centering function for the substrate, itbecomes possible to previously make a center of the movable holdingmember coincide with a center of the substrate-sealing member (and ofthe electrical contact) and, when the movable holding member engages thefixed holding member on which the substrate is placed, shift thesubstrate by the substrate-centering function of the movable holdingmember to a position where the center of the substrate coincides withthe center of the movable holding member. Thus, the center of thesubstrate can be made to coincide with the center of thesubstrate-sealing member (and of the electrical contact for feedingelectricity to the substrate) automatically upon engagement between themovable holding member and the fixed holding member.

In these days, an effective area of a substrate is shifting toward anouter side and a so-called edge exclusion region of the substrate isbecoming extremely narrow. In such a situation, the above substrateholder makes it possible to securely effect sealing of a substrate andelectric feeding to the substrate in this narrow region of thesubstrate.

The present invention provides yet another substrate holder, comprising:a fixed holding member and a movable holding member for holding asubstrate therebetween; a sealing member mounted to the fixed holdingmember or the movable holding member; and at least one pair ofconductors for detecting a liquid leak, which is provided in the fixedholding member and which, when a plating solution leaks to a backsurface side of the substrate held between the movable holding memberand the fixed holding member, short-circuits via this leaked platingsolution.

When a liquid leak occurs and the pair of conductors short-circuits viaa plating solution, an electric current begins to flow between the pairof conductors and an electric resistance changes (becomes not infinite).Accordingly, occurrence of a liquid leak can be detected quickly andsecurely by a simple measurement of the electric resistance.

The pair of conductors is preferably provided at a lower portion of thefixed holding member where leaked plating solution accumulates. Byutilizing the fact that upon leakage of plating solution, this leakedplating solution accumulates at a lower portion of the fixed holdingmember, and thus disposing the conductors at such a local location, aliquid leak can be detected over an entire area of the substrate.

The pair of conductors may be disposed in a loop shape and positionedinside the sealing member when the substrate is held between the movableholding member and the fixed holding member.

The invention provides yet another substrate holder, comprising: a fixedholding member and a movable holding member for holding a substratetherebetween; an inner sealing member for making pressure contact with aperipheral portion of the substrate to seal the peripheral portion; andan outer sealing member, disposed around the substrate, for sealingbetween the fixed holding member and the movable holding member.

By thus providing the two sealing members, i.e. the inner sealing memberand the outer sealing member, to separately effect sealing of aperipheral portion of the substrate with the inner sealing member andsealing between the movable holding member and the fixed holding memberwith the outer sealing member, an improved sealing can be effected.

Preferably, the inner sealing member and the outer sealing member aremounted to the movable sealing member.

Preferably, a step is provided in an outer peripheral portion of themovable holding member and a press ring is rotatably mounted fitly tothe step, and the movable holding member is pressed via the press ringagainst the fixed holding member to hold the substrate.

Preferably, the fixed holding member is provided with a clamper forrestricting movement of the press ring away from the fixed holdingmember.

By thus restricting movement of the press ring, rotatably mounted fitlyto the step provided in an outer peripheral portion of the movableholding member, away from the fixed holding member by the clamperprovided in the fixed holding portion, it becomes possible to shorten adistance between a forefront of the substrate holder and a substratesurface held by the substrate holder, whereby a stirrer (paddle) may bedisposed closer to the substrate surface to thereby improve flow ofplating solution over the surface of the substrate.

The present invention provides a plating apparatus comprising asubstrate holder for holding a substrate and to be transported with thesubstrate while held and immersed in plating solution in a plating tank,the substrate holder comprising: a fixed holding member and a movableholding member for holding a substrate therebetween; a sealing membermounted to the fixed holding member or the movable holding member; and asuction pad for attracting a back surface of the substrate held betweenthe fixed holding member and the movable holding member.

The present invention provides another plating apparatus comprising asubstrate holder for holding a substrate and to be transported with thesubstrate while held and immersed in plating solution in a plating tank,the substrate holder comprising: a fixed holding member and a movableholding member for holding a substrate therebetween; and a sealingmember, mounted to the movable holding member, for making pressurecontact with a peripheral portion of the substrate to seal theperipheral portion, wherein the sealing member is held integrally by aholding member.

The present invention provides yet another plating apparatus comprisinga substrate holder for holding a substrate and to be transported withthe substrate while held and immersed in plating solution in a platingtank, the substrate holder comprising: a fixed holding member and amovable holding member for holding a substrate therebetween; and asealing member, mounted to the movable holding member, for sealingbetween the movable holding member and the fixed holding member, whereinthe sealing member has a W-shaped cross-section, easily collapses whenpressed in a width direction, and recovers by its own elastic force whena pressing force is released.

The present invention provides yet another plating apparatus comprisinga substrate holder for holding a substrate and to be transported withthe substrate held and immersed in a plating solution in a plating tank,the substrate holder comprising: a fixed holding member and a movableholding member for holding a substrate therebetween; a sealing membermounted to the fixed holding member or the movable holding member; and aplate-shaped spring member for biasing the substrate toward the fixedholding member when releasing holding of the substrate between themovable holding member and the fixed holding member.

The present invention provides yet another plating apparatus comprisinga substrate holder for holding a substrate and to be transported withthe substrate while held and immersed in plating solution in a platingtank, the substrate holder comprising: a fixed holding member and amovable holding member for holding a substrate therebetween; a sealingmember mounted to the fixed holding member or the movable holdingmember; and a leaf spring member for making elastic contact with aperipheral portion of the substrate when the substrate is held betweenthe movable holding member and the fixed holding member.

The present invention provides yet another plating apparatus comprisinga substrate holder for holding a substrate and to be transported withthe substrate while held and immersed in plating solution in a platingtank, the substrate holder comprising: a fixed holding member and amovable holding member for holding a substrate therebetween; a sealingmember mounted to the fixed holding member or the movable holdingmember; and at least one pair of conductors for detecting a liquid leak,which is provided in the fixed holding member and which, when a platingsolution leaks to a back surface side of the substrate held between themovable holding member and the fixed holding member, short-circuits viathis leaked plating solution.

The present invention provides yet another plating apparatus comprisinga substrate holder for holding a substrate and to be transported withthe substrate while held and immersed in plating solution in a platingtank, the substrate holder comprising: a fixed holding member and amovable holding member for holding a substrate therebetween; an innersealing member for making pressure contact with a peripheral portion ofthe substrate to seal the peripheral portion; and an outer sealingmember, disposed around the substrate, for sealing between the fixedholding member and the movable holding member.

The present invention provides yet another substrate holder, comprising:a fixed holding member and a moveable holding member for holding asubstrate therebetween; and a sealing member for sealing an outercircumferential end of the substrate when the substrate is held betweenthe movable holding member and the fixed holding member, wherein thefixed holding member has a conductor, and the moveable holding memberhas an electrical contact in the form of a leaf spring member for beingelectrically connected to the conductor in an area sealed by the sealingmember to supply the substrate with electric energy when the substrateis held between the movable holding member and the fixed holding member.

By thus forming the electrical contact in a leaf spring shape andallowing the electrical contact to make contact with the substratethrough elastic force of the electrical contact per se, it becomespossible to reduce poor electrical contact. Further, since a contactportion contacts a peripheral portion, outer of a sealing portion, ofthe substrate, an effective area for pattern formation in the substratecan be broadened.

The electrical contact is preferably adapted to make elastic contactwith a surface of the substrate when the substrate is held between themovable holding member and the fixed holding member.

The electrical contact is preferably adapted to make elastic contactwith an outer circumferential edge of the substrate when the substrateis held between the movable holding member and the fixed holding member.

Since the substrate is biased inwardly by an elastic force of thecontact portion of this leaf spring-shaped electrical contact,positioning (centering) of the substrate relative to the substrateholder upon holding of the substrate by the substrate holder can beeffected by the electrical contact. Further, by providing the movableholding member with the sealing member and the electrical contact, andeffecting positioning (centering) of the substrate relative to thesubstrate holder by the electrical contact, it becomes possible to makea positional relationship between the substrate, the sealing member andthe electrical contact always constant when the substrate is held by thesubstrate holder.

Preferably, the electrical contact has a tip for contacting thesubstrate, with the tip being divided into at least two segments orcomprising parallel segments disposed in respective adjacent positions.With this arrangement, even if dirt or the like is attached to contactportions of some of the electrical contacts, other electrical contactsare kept electrically connected to the substrate.

These divided segments or parallel segments may have portions forcontacting the substrate, with the portions being staggered in a radialdirection of the substrate. With this arrangement, even if the substratesuffers a slight positioning error, at least some of the electricalcontacts are brought into contact with the substrate.

The present invention provides yet another substrate holder, comprising:a fixed holding member and a movable holding member for holding asubstrate therebetween; and a sealing member mounted to the fixedholding member or the movable holding member, wherein the fixed holdingmember and the movable holding member have respective tapered portionsfor engaging each other and positioning the fixed holding member and themovable holding member in central alignment with each other when thesubstrate is held between the movable holding member and the fixedholding member.

By thus providing the fixed holding member and the movable holdingmember with the tapered portions, positioning of the members withrespect to a center can be effected automatically through engagementbetween the tapered portions in the course of holding the substrate bythe members, if the members are not correctly positioned when they areaway from each other.

The tapered portion of the movable holding member is preferably adaptedto guide an outer circumferential edge of the substrate to position thesubstrate when the substrate is held between the movable holding memberand the fixed holding member.

This makes it possible to position the fixed holding member and themovable holding member with respect to the center and position (center)the substrate with respect to the substrate holder simultaneously in thecourse of holding the substrate by the members.

The present invention provides yet another substrate holder, comprising:a fixed holding member and a movable holding member for holding asubstrate therebetween; a sealing member mounted to the fixed holdingmember or the movable holding member; and a springy leaf spring member,mounted to the fixed holding member, which has a free end positionedinwardly of an outer circumferential portion of the substrate when thesubstrate is held between the movable holding member and the fixedholding member, and positioned outwardly of the outer circumferentialportion of the substrate when holding of the substrate between themovable holding member and the fixed holding member is released.

Since movement of the substrate is restricted by a free end of the leafspring member positioned inwardly of an outer circumferential portion ofthe substrate, when the movable holding member is moved after plating torelease holding of the substrate and take the substrate out of thesubstrate holder, the substrate can be prevented from sticking to thesealing member and moving along with the sealing member. With thismovement of the substrate, the free end of the leaf spring member ispositioned outwardly of the outer circumferential portion of thesubstrate, whereby a processed substrate is not prevented from beingtaken out of the substrate holder by the leaf spring member, and asubstrate to be processed is not prevented by the leaf spring memberfrom being inserted in place.

The free end of the leaf spring member is preferably adapted to makeelastic contact with a surface of the substrate when the substrate isheld between the movable holding member and the fixed holding member.

The free end of the leaf spring member is preferably adapted to makeelastic contact with an outer circumferential edge of the substrate whenthe substrate is held between the movable holding member and the fixedholding member. Since the substrate is biased inwardly by an elasticforce of the leaf spring member, positioning (centering) of thesubstrate relative to the substrate holder upon holding of the substrateby the substrate holder can be effected by the leaf spring member.

Preferably, the leaf spring member also serves as an electrical contactfor supplying the substrate with electric energy when the substrate isheld between the movable holding member and the fixed holding member.With this arrangement, it is not necessary to provide a dedicated leafspring member for the sole purpose of separating the substrate from thesealing member when the substrate holder releases the substrate, andhence the substrate holder can be simplified in terms of structure.

The present invention provides yet another substrate holder, comprising:a fixed holding member and a moveable holding member for holding asubstrate therebetween; a sealing member for sealing an outercircumferential end of the substrate when the substrate is held betweenthe movable holding member and the fixed holding member; and a springyleaf spring member for making elastic contact with an outercircumferential edge of the substrate in an area sealed by the sealingmember to position the substrate when the substrate is held between themovable holding member and the fixed holding member.

Since the substrate is biased inwardly by the elastic force of thespringy leaf spring member, positioning (centering) of the substraterelative to the substrate holder upon holding of the substrate by thesubstrate holder can be effected by the leaf spring member. Further, byproviding the movable holding member with the sealing member and theelectrical contact, and effecting positioning (centering) of thesubstrate relative to the substrate holder by the electrical contact, itbecomes possible to make a positional relationship between thesubstrate, the sealing member and the electrical contact always constantwhen the substrate is held by the substrate holder.

It is preferred that the movable holding member further comprises anelectrical contact for making elastic contact with the substrate tosupply the substrate with electric energy when the substrate is heldbetween the movable holding member and the fixed holding member.

The present invention provides yet another substrate holder, comprising:a fixed holding member and a moveable holding member for holding asubstrate therebetween; and a sealing member for sealing an outercircumferential end of the substrate when the substrate is held betweenthe movable holding member and the fixed holding member, wherein thesealing member has lips for contacting a peripheral portion of thesubstrate and a surface of the fixed holding member, respectively, whenthe substrate is held between the movable holding member and the fixedholding member, and is integrally held by a support body which ismounted in a place between the lips.

Since the sealing member is thus integrally held by a support body, whenthe movable holding member is moved after plating to release holding ofthe substrate and the substrate is taken out of the substrate holder, asealing portion of the sealing member can be prevented from adhering tothe substrate, and the sealing member can be prevented from being tornoff from the holding member. Releasability of the sealing member fromthe substrate can thus be improved.

The present invention provides yet another plating apparatus comprisinga substrate holder for holding a substrate and to be transported withthe substrate while held and immersed in plating solution in a platingtank, the substrate holder comprising: a fixed holding member and amoveable holding member for holding a substrate therebetween; and asealing member for sealing an outer circumferential end of the substratewhen the substrate is held between the movable holding member and thefixed holding member, wherein the fixed holding member has a conductor,and the moveable holding member has an electrical contact in the form ofa leaf spring member for being electrically connected to the conductorin an area sealed by the sealing member to supply the substrate withelectric energy when the substrate is held between the movable holdingmember and the fixed holding member.

The present invention provides yet another plating apparatus comprisinga substrate holder for holding a substrate and to be transported withthe substrate while held and immersed in plating solution in a platingtank, the substrate holder comprising: a fixed holding member and amovable holding member for holding a substrate therebetween; and asealing member mounted to the fixed holding member or the movableholding member, wherein the fixed holding member and the movable holdingmember have respective tapered portions for engaging each other andpositioning the fixed holding member and the movable holding member incentral alignment with each other when the substrate is held between themovable holding member and the fixed holding member.

The present invention provides yet another plating apparatus comprisinga substrate holder for holding a substrate and to be transported withthe substrate while held and immersed in plating solution in a platingtank, the substrate holder comprising: a fixed holding member and amovable holding member for holding a substrate therebetween; a sealingmember mounted to the fixed holding member or the movable holdingmember; and a springy leaf spring member, mounted to the fixed holdingmember, which has a free end positioned inwardly of an outercircumferential portion of the substrate when the substrate is heldbetween the movable holding member and the fixed holding member, andpositioned outwardly of the outer circumferential portion of thesubstrate when holding of the substrate between the movable holdingmember and the fixed holding member is released.

The present invention provides yet another plating apparatus comprisinga substrate holder for holding a substrate and to be transported withthe substrate while held and immersed in plating solution in a platingtank, the substrate holder comprising: a fixed holding member and amoveable holding member for holding a substrate therebetween; a sealingmember for sealing an outer circumferential end of the substrate whenthe substrate is held between the movable holding member and the fixedholding member; and a springy leaf spring member for making elasticcontact with an outer circumferential edge of the substrate in an areasealed by the sealing member to position the substrate when thesubstrate is held between the movable holding member and the fixedholding member.

The present invention provides yet another plating apparatus comprisinga substrate holder for holding a substrate and to be transported withthe substrate while held and immersed in plating solution in a platingtank, the substrate holder comprising: a fixed holding member and amoveable holding member for holding a substrate therebetween; and asealing member for sealing an outer circumferential end of the substratewhen the substrate is held between the movable holding member and thefixed holding member, wherein the sealing member has lips for contactinga peripheral portion of the substrate and a surface of the fixed holdingmember, respectively, when the substrate is held between the movableholding member and the fixed holding member, and is integrally held by asupport body which is mounted in a place between the lips.

The above and other objects, features, and advantages of the presentinvention will be apparent from the following description when taken inconjunction with the accompanying drawings which illustrates preferredembodiments of the present invention by way of example.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a layout plan of a plating apparatus provided with a substrateholder according to an embodiment of the present invention;

FIG. 2 is a plan view of the substrate holder shown in FIG. 1;

FIG. 3 is a sectional right side view of the substrate holder shown inFIG. 1;

FIG. 4 is a vertical sectional front view of the substrate holder shownin FIG. 1;

FIGS. 5A through 5C are diagrams illustrating a relationship between aconductor, an electrical contact and a substrate in the course ofholding of the substrate by the substrate holder shown in FIG. 1;

FIGS. 6A through 6C are diagrams illustrating a relationship between atapered portion of a fixed holding member and a tapered portion of amovable holding member in the course of holding of a substrate by thesubstrate holder shown in FIG. 1;

FIG. 7 is a cross-sectional view of a portion of the substrate holdershown in FIG. 1 in which a suction pad is provided;

FIG. 8 is a cross-sectional view showing a state of the substrate holderwhen it is locked by a locking/unlocking mechanism;

FIG. 9 is a plan view of the locking/unlocking mechanism;

FIGS. 10A through 10C are diagrams illustrating a relationship between aleaf spring member and a substrate in the course of holding of thesubstrate by the substrate holder;

FIG. 11 is a cross-sectional view of a laminated leaf spring as a leafspring member;

FIG. 12 is a plan view of another inner sealing member;

FIGS. 13A and 13B are enlarged views of portion A of FIG. 12;

FIG. 14 is a transverse sectional view of FIG. 12;

FIG. 15 is a plan view of a substrate holder according to anotherembodiment of the present invention;

FIG. 16 is a plan view of a substrate holder according to yet anotherembodiment of the present invention;

FIG. 17 is a plan view of a substrate holder according to yet anotherembodiment of the present invention;

FIG. 18 is a vertical sectional front view of the substrate holder shownin FIG. 17;

FIG. 19 is a sectional right side view of the substrate holder shown inFIG. 17;

FIG. 20A is a cross-sectional view showing a conductor and an electricalcontact of the substrate holder shown in FIG. 17 before holding of asubstrate;

FIG. 20B is a cross-sectional view showing the conductor and theelectrical contact of the substrate holder shown in FIG. 17 afterholding of a substrate;

FIG. 21A is a cross-sectional view showing tapered portions of a fixedholding member and a movable holding member of the substrate holderbefore holding of a substrate;

FIG. 21B is a cross-sectional view showing the tapered portions of thefixed holding member and the movable holding member of the substrateholder after holding of a substrate;

FIGS. 22A through 22F are diagrams illustrating, in a sequence of steps,a relationship between a leaf spring member and a member that engagesthe leaf spring member to deform the leaf spring member;

FIG. 23A is a cross-sectional view of another electrical contact beforeholding of a substrate;

FIG. 23B is a cross-sectional view of the another electrical contactafter holding of a substrate;

FIGS. 24A through 24F are diagrams illustrating, in a sequence of steps,a relationship between an electrical contact/leaf spring member, servingboth as an electrical contact and as a leaf spring member, and a memberthat engages the electrical contact/leaf spring member to deform theelectrical contact/leaf spring member;

FIG. 25A is a cross-sectional view of a leaf spring member that effectspositioning of a substrate before holding of the substrate;

FIG. 25B is a cross-sectional view of a leaf spring member that effectspositioning of a substrate after holding of the substrate;

FIGS. 26A through 26D are plan views showing different electricalcontacts, respectively; and

FIGS. 27A through 27D are diagrams illustrating, in a sequence ofprocess steps, formation of bumps (protruding electrodes) on asubstrate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be describedwith reference to drawings.

FIG. 1 shows a layout plan of a plating apparatus provided with asubstrate holder according to an embodiment of the present invention. Asshown in FIG. 1, the plating apparatus includes two cassette tables 12each for placing thereon a cassette 10 for housing substrates W such assemiconductor wafers, an aligner 14 for aligning a position of anorientation flat or a notch of substrate W in a predetermined direction,and a spin drier 16 for rotating the substrate W after plating at a highspeed to dry the substrate. Further, a substrate attaching/detachingsection 20 for placing thereon a substrate holder 18 for detachablyholding the substrate W, and attaching/detaching the substrate W to/fromthe substrate holder 18, is provided near the spin drier 16.Furthermore, a substrate transfer device 22, comprised of a transferrobot, is disposed centrally above units for transferring the substrateW between the units.

The plating apparatus also includes, disposed in order from thesubstrate attaching/detaching section 20 side, a stocker 24 for stockingand temporarily housing the substrate holder 18, a pre-wetting tank 26for immersing the substrate W in pure water, a presoaking tank 28 foretching away an oxide film on a seed layer 500 (see FIGS. 27A to 27C)formed on a surface of the substrate W, a first water-washing tank 30 afor washing the surface of the substrate W with pure water, a blow tank32 for draining (drying) the substrate W after washing, a secondwater-washing tank 30 b, and a plating tank 34. The plating tank 34houses a plurality of copper plating units 38 in an overflow tank 36.Each copper plating unit 38 houses one substrate W to perform copperplating of the substrate. Though copper plating is performed in thisembodiment, the plating apparatus is of course applicable to other typesof plating, such as nickel, solder, silver and gold plating.

Further, positioned on one side of the above devices and tanks, there isprovided a substrate holder transport device 40, which employs e.g. alinear motor system, for transporting the substrate holder 18 togetherwith the substrate W between the devices and tanks. The substrate holdertransport device 40 includes a first transporter 42 for transporting thesubstrate W between the substrate attaching/detaching section 20 and thestocker 24, and a second transporter 44 for transporting the substrate Wbetween the stocker 24, the pre-wetting tank 26, the presoaking tank 28,the water-washing tanks 30 a, 30 b, the blow tank 32 and the platingtank 34. In this regard, it is possible to provide only the firsttransporter 42 without providing the second transporter 44.

On an opposite side of the overflow tank 36 from the substrate transportdevice 40 are disposed paddle drive devices 46 for driving a paddle (notshown) provided in each copper plating unit 38 as a stirrer for stirringa plating solution.

The substrate attaching/detaching section 20 includes a tabular loadingplate 52 which is slidable laterally along rails 50. Two substrateholders 18 are placed horizontally and in parallel on the loading plate52. After one substrate W is transferred between one substrate holder 18and the substrate transfer device 22, the loading plate 52 is slidlaterally so that another substrate is transferred between the othersubstrate holder 18 and the substrate transfer device 22.

As shown in FIGS. 2 through 7, the substrate holder 18 includes arectangular tabular fixed holding member 54 made of, for example, avinyl chloride resin, and a movable holding member 58 mounted openablyand closably via a hinge 56 on the fixed holding member 54. Though inthis embodiment the movable holding member 58 is designed to be openableand closable by the hinge 56, it is also possible, for example, todispose the movable holding member 58 opposite to the fixed holdingmember 54, and open and close the movable holding member 58 by moving itto and away from the fixed holding member 54.

The movable holding member 58 includes a base portion 58 a and a supportportion 58 b which has a ring shape according to this embodiment. Themovable holding member 58 is made of, for example, a vinyl chlorideresin so that it exhibits good slippage with below-described press ring60. On a far side surface of the support portion 58 b from the fixedholding member 54 is mounted by bolts 64 (see FIGS. 6A to 6C) aninwardly protruding sealing member (hereinafter referred to as “innersealing member”) 62 for contacting a peripheral portion of the substrateW to seal the portion. On the other hand, a dovetail-shaped seal groove66 is formed in a surface of the support portion 58 b on the holdingmember 54 side, and a sealing member (hereinafter referred to as “outersealing member”) 68 for sealing the fixed holding member 54 and themovable holding member 58 is fitted into the seal groove 66.

The inner sealing member 62 is to make pressure contact with aperipheral portion of a surface (to-be-plated surface) of the substrateW when it is held by the substrate holder 18, thereby sealing thatportion, and has at its inner periphery a steeple-shaped sealing portion62 a which protrudes downwardly and makes linear contact with theperipheral portion of the substrate W. The inner sealing member 62 ismounted integrally on a holding member 70, made of e.g. titanium, whichholds the sealing member 62. In particular, the inner sealing member 62is attached to the holding member 70 such that the sealing member 62covers almost the entire surface of the holding member 70, therebypreventing the sealing member 62 from peeling or falling from theholding member 70.

Since the inner sealing member 62 is thus integrally mounted on theholding member 70, when the movable holding member 58 is moved afterplating to release holding of the substrate W and the substrate W istaken out of the substrate holder 18, the sealing portion 62 a of theinner sealing member 62 can be prevented from adhering to the substrateW, and hence the inner sealing member 62 can be prevented from beingtorn off from the holding member 70. Releasability of the sealing member62 from the substrate W can thus be improved. Further, since the innersealing member 62 makes linear contact with the substrate W, sealing canbe effected securely at a low clamping pressure and, in addition, aneffective area for pattern formation in the substrate W can bebroadened.

The inner sealing member 62, mounted integrally to the holding member70, is mounted by bolts 64 to the support portion 58 b of the movableholding member 58. A ring-shaped sealing member 71 is interposed betweenthe inner sealing member 62 and the support portion 58 b. The bolts 64are disposed outside of the sealing member 71, and the inner sealingmember 62 is fixed to the support portion 58 b by fastening the bolts 64to squash the sealing member 71. This prevents leakage of water from aninterstice between the inner sealing member 62 and the holding portion58 b, shown by the arrow in FIG. 6A, or from portions where the bolts 64are fixed.

The outer sealing member 68, on the other hand, is to make pressurecontact with a movable holding member 58 side surface of the fixedholding member 54 to seal the contact portion when the substrate W isheld by the substrate holder 18. According to this embodiment, the outersealing member 68 has a W-shaped cross-section, has sealing portions 68a, 68 b in lower and upper surfaces at almost a center in a widthdirection, and broadens toward a bottom of the seal groove 66. When abroad portion of the outer sealing member 68 is pressed in the widthdirection, the portion easily collapses and narrows. Upon release of apressing force, the portion recovers by elastic force. When fitting theouter sealing member 68 into the dovetail-shaped seal groove 66, thebroad portion of the outer sealing member 68 is collapsed in the widthdirection, thereby facilitating insertion of the outer sealing member 68into the seal groove 66. After this insertion, the outer sealing member68 expands by elastic force, whereby the sealing member can be preventedfrom falling from the seal groove 66.

As shown in FIG. 7, there is a cut-away portion 66 a formed in themovable holding member 58 which is necessary for removal of a tool uponformation of the dovetail-shaped seal groove 66. There is, therefore, afear that a plating solution would intrude from the cut-away portion 66a into the seal groove 66 and, due to denaturing or solidification ofthe plating solution, a sealing ability of the outer sealing member 68would be lowered. In this regard, according to this embodiment, sidesurfaces of the outer sealing member 68 are in contact with sidewallsurfaces of the seal groove 66 with a certain elastic force. Thispresents the above-described intrusion of plating solution, therebyensuring sealing and enhancing durability of the outer sealing member68.

A step is provided in an outer peripheral portion of the movable holdingmember 58, and press ring 60 is fitly supported unescapably androtatably to the step by press plates 72. The press ring 60 is made of,for example, titanium that is highly resistant to an oxidizingatmosphere and has sufficient rigidity.

Positioned outside the press ring 60, inversed L-shaped clampers 74,each having an inwardly protruding portion, are mounted vertically onthe fixed holding member 54 at regular intervals along a circumferentialdirection of the fixed holding member 54. An upper surface of eachoutwardly protruding portion of the press ring 60 and a lower surface ofthe inwardly protruding portion of each clamper 74 are taperedcircumferentially in opposite directions. Further, a plurality of longholes 60 a (e.g. four holes) are formed in the press ring 60 along acircumferential direction. As will be described below, rotating pins 112are inserted into the long holes 60 a, and the pins 112 are rotated tothereby rotate the press ring 60.

When the movable holding member 58 is open, the substrate W is insertedinto a center of the fixed holding member 54, and then the movableholding member 58 is closed by the hinge 56. The press ring 60 isrotated clockwise so as to slip the outwardly protruding portions of thepress ring 60 in under the inwardly protruding portions of the clampers74. The fixed holding member 54 and the movable holding member 58 arefastened to each other via the tapered surfaces of the press ring 60 andthe clampers 74, whereby the movable holding member 58 is locked. Thislocking is released by rotating the press ring 60 counterclockwise andthereby drawing the outwardly protruding portions of the press ring 60from the inversed L-shaped clampers 74. When the movable holding member58 is thus locked, the sealing portion 62 a of the inner sealing member62 is in pressure contact with the surface of the substrate W, whilewith respect to the outer sealing member 68, the sealing portion 68 a isin pressure contact with a surface of the fixed holding member 54 andthe sealing portion 68 b is in pressure contact with a bottom surface ofthe seal groove 66. The sealing members 62, 68 are respectively under auniform pressure so that a sufficient sealing is ensured.

In the center of the fixed holding member 54 is provided an upwardlyprotruding ring-shaped ridge 82 with its size meeting a size of thesubstrate W. An upper surface of the ridge 82 serves as a supportsurface 80 that contacts a peripheral portion of the substrate W andsupports the substrate W. Recesses 84 are formed in the ridge 82 atcertain locations along a circumferential direction.

As shown in FIG. 2 and FIGS. 5A through 5C, a plurality of conductors(electrical contacts) 86 (twelve conductors are shown in FIG. 2) isdisposed in the recesses 84, which conductors 86 are respectivelyconnected to a plurality of wires extending from external contactsprovided in below-described hands 120. When the substrate W is placed onthe support surface 80 of the fixed holding member 54, end portions ofthe conductors 86 with spring properties are exposed on the surface ofthe fixed holding member 54, and are beside the substrate W.

On the other hand, a leg portion 88 a each of electrical contacts 88 isfixed to the support portion 58 b of the movable holding member 58 at alocation where it is opposed to each conductor 86. The electricalcontact 88 is formed in a leaf spring shape, and has a positioning(centering) function for the substrate W and a function of preventingthe substrate W from sticking to the sealing portion 62 a of the innersealing member 62 and being brought up along with the sealing portion 62a when taking the substrate W after plating out of the substrate holder18. Thus, the electrical contact 88 has a contact portion 88 bpositioned below the inner sealing member 62 and protruding inwardly ina leaf spring shape. The contact portion 88 b bends easily due to itsspring properties and, when the substrate W is held by the fixed holdingmember 54 and the movable holding member 58, makes elastic contact witha peripheral portion of the substrate W supported on the support surface80 of the fixed holding member 54.

When the substrate W is placed on the support surface 80 of the fixedholding member 54 as shown in FIG. 5A, and the movable holding member 58is then moved to the fixed holding member 54 to lock the movable holdingmember 58 and hold the substrate W as shown in FIGS. 5B and 5C, anexposed portion of the conductor 86, by its elastic force, makes anelastic contact with a lower surface of the leg portion 88 a of theelectrical contact 88 to thereby make an electrical connection, and thecontact portion 88 b of the electrical contact 88, by its elastic force,makes an elastic contact with the substrate W. Feeding of electricity tothe substrate W via the electrical contacts 88 can thus be effectedwhile the substrate W is held with the substrate holder 18 and sealedwith the sealing members 62, 68.

By thus forming each electrical contact 88 in a leaf spring shape andallowing a front end of the contact portion 88 b of the electricalcontact 88 to make contact with the substrate W through the elasticforce of the electrical contact 88 per se, it becomes possible to reducepoor electrical contact. Further, since the contact portion 88 bcontacts a peripheral portion, outer of a sealing portion, of thesubstrate W, an effective area for pattern formation in the substrate Wcan be broadened. Further, since the substrate W is biased inwardly bythe elastic force of the contact portion 88 b of the leaf spring-shapedelectrical contact 88, positioning (centering) of the substrate Wrelative to the substrate holder 18 upon holding of the substrate by thesubstrate holder 18 can be effected by the electrical contact 88.Furthermore, by providing the movable holding member 58 with the innersealing member 62 and the electrical contacts 88, and effectingpositioning of the substrate W relative to the substrate holder 18 bythe electrical contacts 88, it becomes possible to make a positionalrelationship between the substrate W, the sealing member 62 and theelectrical contacts 88 always constant when the substrate W is held bythe substrate holder 18.

When taking the substrate W out of the substrate holder 18 aftercompletion of a series of processings, the movable holding member 58 ismoved away from the fixed holding member 54. During this movement, asshown in FIGS. 5C and 5B, the contact portion 88 b of each electricalcontact 88 is in pressure contact with the peripheral portion of thesubstrate W so that the substrate W is biased downwardly. Movement ofthe substrate W is thus restricted by the electrical contacts 88.Accordingly, if the sealing member 62 sticks to the substrate W, onlythe sealing member 62 and the movable holding member 58 move upward,whereas the substrate W is forcibly detached from the sealing member 62.When the movable holding member 58 further moves upward, the contactportions 88 b of the electrical contacts 88 detach from the substrate W,returning to a position shown in FIG. 5A.

Thus, when the movable holding member 58 is moved after plating torelease holding of the substrate W and take the substrate W out of thesubstrate holder 18, the substrate W can be prevented from sticking tothe sealing member 62 and moving along with the sealing member 62.

With reference to the conductor 86, it is preferred that at least asurface to make contact with the electrical contact 88 have a coating ofe.g. gold or platinum plating.

As shown in FIGS. 6A to 6C, the ridge 82 of the fixed holding member 54partly has a tapered portion 82 a with a steeple-shaped tapered surface,while the support portion 58 b of the movable holding member 58 has inits inner circumferential surface a tapered portion 90 to be opposed tothe tapered portion 82 a and having a reverse tapered surface relativeto the tapered surface of the tapered portion 82 a. When the substrate Wis held with the fixed holding member 54 and the movable holding member58, the tapered portion 82 a and the tapered portion 90 engage eachother to effect positioning of the members 54, 58 with respect to acenter. Thus, when the substrate W is placed on the support surface 80of the fixed holding member 54 as shown in FIG. 6A, and the movableholding member 58 is then moved to the fixed holding member 54 to lockthe movable holding member 58 and hold the substrate W as shown in FIGS.6B and 6C, the tapered portions 82 a, 90 serve as a mutual guide forpositioning of the movable holding member 58 relative to the fixedholding member 54, or vice versa.

By thus providing the ridge 82 of the fixed holding member 54 and thesupport portion 58 b of the movable holding member 58 with the taperedportions 82 a, 90, positioning of the members 54, 58 with respect to thecenter can be effected automatically through engagement between thetapered portions 82 a, 90 in the course of holding the substrate W bythe members 54, 58, if the members 54, 58 are not correctly positionedwhen they are away from each other.

As described above, positioning of the fixed holding member 54 and themovable holding member 58 with respect to the center and positioning(centering) of the substrate W with respect to the substrate holder 18,and thus with respect to the inner sealing member 62, can be effectedsimultaneously in the course of holding the substrate W by the members54, 58.

However, a precise centering can be effected with difficulty onlythrough engagement between the tapered portions 82 a, 90. This isbecause a clearance, if small, is necessary between the two taperedportions 82 a, 90 in order to facilitate engagement therebetween.Accordingly, a center of the substrate W inevitably deviates from thecenter of the movable holding member 58 by the clearance. In view ofthis, the movable holding member 58 is provided with a plurality of leafspring members 140, as will be described later. The leaf spring members140 make elastic contact with a peripheral edge of the substrate W andevenly apply a pressing force acting to move the substrate W toward thecenter of the movable member 58. Accordingly, when the movable holdingmember 58 engages the fixed holding member 54, the substrate W isshifted so that the center of the substrate can coincide exactly withthe center of the movable holding member 58. It is of course possiblethat a plurality of leaf springs take the form of an integral structurethat surrounds a periphery of the substrate.

Further, the movable holding member and the fixed holding member are notnecessarily coupled by the hinge, and may of course be separated.

As shown in FIG. 2, relatively wide recesses 92 are formed in the ridge82 of the fixed holding member 54 on a far side from the hinge 56 at twolocations according to this embodiment. A suction pad 94 is housed ineach recess 92. As shown in detail in FIG. 7, the suction pad 94 is madeof a flexible material, such as rubber, has a conical cup 96 having adecompression portion inside, and is mounted by a bolt 100 on the fixedholding member 54. When the substrate W is held by the substrate holder18, the substrate W presses an opening of the cup portion 96 and expandsthe cup portion 96 outwardly, so that air in the suction pad 94 isforced out and the pressure in the decompression portion is reduced,whereby a back surface of the substrate W is attracted by suction to thesuction pad 94.

Since the back surface of the substrate W is kept attracted to thesuction pad 94, when the movable holding member 58 is moved afterplating to release holding of the substrate W and take the substrate Wout of the substrate holder 18, the substrate W can be prevented fromsticking to the sealing member 62 and moving along with the sealingmember 62. Further, since the substrate W is thus prevented from beingbrought upward, when performing an automatic operation using anautomatic transport device, the substrate W can be taken out of thesubstrate holder 18 stably. An attraction force of the suction pad 94 isset at such a degree that when taking the substrate W out of thesubstrate holder 18 in the above-described manner, the substrate W canbe moved horizontally away from the cup portion so that a vacuum can bebroken, the substrate W can be easily separated from the sealing member62, and the substrate W can be transferred to a robot. Thus, the suctionpad 94 has a strong adhesion to the substrate W in a vertical direction,and therefore is effective for holding of the substrate, while it allowsthe substrate W to move horizontally and detach from it easily.

Though a location and number of suction pads 94 may be determinedarbitrarily, it is preferred to locate a suction pad 94 on an oppositeside of the center of the substrate W, held by the substrate holder 18,from the hinge 64 and at a position corresponding a peripheral portionof the substrate W. A suction pad 94 at such a location prevents, whenopening the movable holding member 58 via the hinge 56, that peripheralportion of the substrate W from sticking to the inner sealing member 62and being brought up, which portion would otherwise be first brought up,and can effectively separate the substrate W from the inner sealingmember 62.

It is also possible to use a suction pad of a so-called vacuumattraction type. In particular, though not shown diagrammatically, avacuum line extends in an interior of the fixed holding member 54 andcommunicates with an interior of the suction pad. When the substrate isheld by the substrate holder 18, the interior of the suction pad isvacuumed through the vacuum line, thereby attracting the substrate andholding it on the pad easily and securely. This holding of the substratecan be released by stopping vacuuming.

Opening and closing of the movable holding member 58 is performedthrough a not-shown cylinder and weight of the movable holding member 58per se. In particular, as shown in FIG. 3, a through-hole 54 a is formedin the fixed holding member 54 and the cylinder is provided at alocation where the cylinder faces the through-hole 54 a when thesubstrate holder 18 is placed on the loading plate 52. The movableholding member 58 is opened by extending a cylinder rod and allowing apressing rod to pass through the through-hole 54 and press up the baseportion 58 a of the movable holding member 58, while the holding member58 is closed by its own weight by retracting the cylinder rod.

According to this embodiment, locking/unlocking of the movable holdingmember 58 is effected by rotating the press ring 60. FIGS. 8 and 9 showa locking/unlocking mechanism 110. The locking/unlocking mechanism 110is provided on a ceiling side, and includes rotating pins 112 each at alocation corresponding to each long hole 60 a of the press ring 60 ofthe movable holding member 58 when the substrate W is placed in thesubstrate holder 18 on the loading plate 52 and the movable holdingmember 58 is closed via the hinge 56. The rotating pins 112 are mountedvertically to a lower surface of a rotary plate 114 which is rotatablein both directions. The locking/unlocking mechanism 110 is also providedwith vertically movable pressing rods 116 for pressing the supportportion 58 b of the movable holding member 58 of the substrate holder 18on the loading plate 52 against the fixed holding member 54. In therotary plate 114 are formed circumferentially extending long holes 114 aat locations corresponding to the pressing rods 116.

In operation, the substrate holder 18, with the substrate W placedtherein and the movable holding member 58 closed, is raised along withthe loading plate 52 so as to locate the rotating pins 112 in the longholes 60 a of the press ring 60. Thereafter, the pressing rods 116 arelowered to press the movable holding member 58 downward, therebycollapsing the sealing members 62, 68 so that the movable holding member58 will not rotate. The rotating pins 112 are then rotated to therebyrotate the press ring 60, whereby each of outwardly protruding portionsof the press ring 60 is slipped into each of the clampers 74 to lock themovable holding member 58.

By thus first lowering the pressing rods 116 so as to inhibit rotationof the movable holding member 58 and then rotating the press ring 60 viathe rotating pins 112, the press ring 60 can be rotated with lowfriction. This reduces wear of the press ring 60, the clampers 74 andthe movable holding member 58, and prevents the movable holding member58 from co-rotating with the press ring 60, thereby preventing adisplacement of the movable holding member 58 which would affectcentering of the substrate W and distort the sealing members 62,68 tolower their sealing abilities.

It is possible to use a ring-shaped rotator instead of the rotary plate114. Further, instead of the pressing rods 116, it is possible to use acylindrical pressing member 116 a as shown by the shaded area of FIG. 9so that an entire peripheral edge area of the substrate support 58 b ofthe movable holding member 58 can be pressed evenly.

A single locking/unlocking mechanism 110 is provided. After locking (orunlocking) one of two substrate holders 18 placed on the loading plate52, the loading plate 52 is slid laterally to lock (or unlock) the othersubstrate holder 18 with the locking/unlocking mechanism 110. Thesubstrate holder 18 is provided with a sensor for inspecting a state ofcontact between the substrate W and the contacts of the substrate holder18 when the substrate is held by the substrate holder 18. A signal fromthe sensor is inputted to a controller (not shown).

To one end of the fixed holding member 54 of the substrate holder 18 isjointed a pair of substantially T-shaped hands 120 which serves as asupport when the substrate holder 18 is transported or held in a hungstate. In the stocker 24, the holder 18 is held in a vertically hungstate with protruding end portions of the hands 120 put on an uppersurface of a circumferential wall of the stocker 24. The hands 120 ofthis thus hung substrate holder 18 are grasped by the transporter 42 ofthe substrate transport device 40 when transporting the substrate holder18. Also in the pre-wetting tank 26, the presoaking tank 28, thewater-washing tanks 30 a, 30 b, the blow tank 32 and the plating tank34, the substrate holder 18 is held in a hung state with the hands 120on a upper surface of a circumferential wall of each tank.

Next, a plating process will be described for plating a series of bumpelectrodes using the plating apparatus described above. As shown in FIG.27A, a seed layer 500 as an electric feed layer is formed on a surfaceof a substrate. A resist 502 having a height H of e.g. 20-120 μm isapplied over an entire surface of the seed layer 500. Subsequently, anopening 502 a having a diameter D of e.g. 20-200 μm is formed at aprescribed position in the resist 502. Such a substrate W is housed inthe cassette 10 with a surface (surface to be plated) facing upward. Thecassette 10 is loaded onto the cassette table 12.

The substrate transfer device 22 takes out one substrate from thecassette 10 on the cassette table 12 and places the substrate on thealigner 14. The aligner 14 aligns an orientation flat or notch or thelike in a prescribed orientation. Next, the substrate transfer device 22transfers this aligned substrate W to the substrate attaching/detachingsection 20.

In the substrate attaching/detaching section 20, two substrate holders18 housed in the stocker 24 are gripped simultaneously by thetransporter 42 of the substrate holder transport device 40, andtransported to the substrate attaching/detaching section 20. Thesubstrate holders 18 are lowered in a horizontal state, and placed onthe loading plate 52 of the substrate attaching/detaching section 20simultaneously. The cylinders are operated to open the moveablesupporting members 58 of the substrate holders 18.

While the moveable supporting members 58 are open, the substratetransfer device 22 inserts the substrate into one of the substrateholders 18 positioned in a center of the substrate attaching/detachingsection 20. The cylinder performs a reverse operation to close themoveable supporting member 58. Subsequently, the moveable supportingmember 58 is locked by the locking/unlocking mechanism 110. After onesubstrate W is loaded into one substrate holder 18, the loading plate 52is slid horizontally to load another substrate in the other substrateholder 18. Subsequently, the loading plate 52 is returned to itsoriginal position.

Thus, each surface of the substrate to be plated is exposed in theopening portion of the substrate holder 18. The sealing members 62, 68seal the peripheral portion of the substrates W to prevent platingsolution from entering thereinto. Electricity is continued through theplurality of contacts in areas not in contact with the plating solution.Wiring is connected from the contacts to the hands 120 of the substrateholder 18. By connecting a power source to the hands 120, electricitycan be supplied to the seed layer 500 formed on the substrate.

Next, the transporter 42 of the substrate holder transport device 40grips both of the substrate holders 18 holding the substratesimultaneously, and transports the substrate holders 18 to the stocker24. The substrate holders 18 are lowered with horizontal state so thattwo substrate holders 18 are suspended (temporary placement) in thestocker 24.

The above process performed by the substrate transfer device 22, thesubstrate attaching/detaching section 20, and the transporter 42 of thesubstrate holder transport device 40 is repeated in order to loadsubstrate W one after another into the substrate holder 18 housed in thestocker 24 and suspend (temporary placement) the substrate holder 18 oneafter another at prescribed positions in the stocker 24.

When the sensor mounted on the substrate holder 18 for inspecting acontact state between the substrate and the contacts determines a poorcontact, the sensor inputs a signal into a controller (not shown).

Meanwhile, the other transporter 44 of the substrate transport device 40simultaneously grips two substrate holders 18 that have been holding thesubstrates and temporarily placed in the stocker 24. The transporter 44transports the substrate holders 18 to the pre-wetting tank 26 andlowers to enter the substrate holders 18 into the pre-wetting tank 26.

However, if the sensor mounted on the substrate holder 18 for inspectingthe contact state between the substrate and contacts has detected a poorcontact state, the substrate holder 18 holding the substrate having thepoor contact is left stored in the stocker 24. Accordingly, when a poorcontact between a substrate and the contacts of the substrate holder 18occurs, it does not halt the apparatus, but allows plating operations tocontinue. The substrate with a poor contact is not subjected to aplating process. Instead the substrate is returned to a cassette anddischarged from the cassette.

Next, the substrate holders 18 holding the substrates are transported inthe same way as described above to the presoaking tank 28 and oxidelayers of the substrates are etched away in the presoaking tank 28 toexpose a clean metal surface. Next, the substrate holders 18 holding thesubstrates are transported in the same way to the cleaning tank 30 a,wherein the surfaces of the substrates are cleaned by pure water heldtherein.

After the cleaning process, the substrate holders 18 holding thesubstrates are transported in the same way as described above to theplating tank 34 and suspended in the plating units 38. The transporter44 of the substrate holder transport device 40 repeatedly performs thisoperation of transporting the substrate holder 18 to the plating unit 38and suspending the substrate holder 18 at a prescribed position therein.

When all the substrate holders 18 are suspended in the plating units 38,plating voltages are applied between anodes (not shown) and thesubstrates, while plating solution in the overflow tank 36 iscirculating and overflowing into the overflow tank 36. At the same time,the paddle drive devices 46 reciprocate the paddles in a directionparallel to surfaces of the substrates, thereby plating the surfaces ofthe substrates. At this time, each of the substrate holders 18 is fixedin a suspended state by the hands 120 at a top of the plating unit 38.Electricity is supplied from a plating power source to the seed layer500 (see FIGS. 27A to 27C) via the conductors 86 and the electricalcontacts 88.

After completion of this plating process, application of platingvoltages, supply of plating solution, and reciprocation of the paddlesare all stopped. The transporter 44 of the substrate holder transportdevice 40 grips two of the substrate holders 18 holding the substratessimultaneously, and transports the substrate holders 18 to the cleaningtank 30 b, as described above. The substrate holders 18 are immersed inpure water held in the cleaning tank 30 b to clean surfaces of thesubstrates W. Subsequently, the substrate holders 18 are transferred asdescribed above to the blowing tank 32, where air is blown onto thesubstrate holders 18 holding the substrates to remove water dropletsdeposited thereon. Next, the substrate holders 18 are returned andsuspended at prescribed positions in the stocker 24, as described above.

The above operation of the transporter 44 of the substrate holdertransport device 40 is repeatedly conducted. After each substrate W hasbeen subjected to this complete plating process, the substrate holders18 are returned to the prescribed suspended position in the stocker 24.

Meanwhile, the transporter 42 of the substrate holder transport device40 simultaneously grips two of the substrate holders 18 holding thesubstrates that have been returned to the stocker 24 after the platingprocess, and places the substrate holders 18 on the loading plate 52 ofthe substrate attaching/detaching section 20, as described above. Atthis time, a substrate for which a poor connection was detected by thesensor mounted on the substrate holders 18 for inspecting a contactstate between the substrate and contacts, and which was left in thestocker 24, is also transported to the loading plate 52.

Next, the moveable supporting member 58 in the substrate holder 18positioned at the center of the substrate attaching/detaching section 20is unlocked by the locking/unlocking mechanism 110. The cylinder isoperated to open the moveable supporting member 58. At this time, asdescribed above, the substrate W can be prevented from sticking to themoveable supporting member 58 when the moveable supporting member 58 isopened. In this state, the substrate transfer device 22 takes a platingprocessed substrate out of the substrate holder 18 and transfers thesubstrate to the spin dryer 16. The spin dryer 16 spins the substrate ata high rotational speed for spin-drying (draining). The substratetransfer device 22 then transfers the substrate back to the cassette 10.

After the substrate is returned to the cassette 10, or during thisprocess, the loading plate 52 is slid laterally, and the same process isperformed for a substrate mounted in the other substrate holder 18 sothat this substrate is spin-dried and returned to the cassette 10.

The loading plate 52 is returned to its original position. Next, thetransporter 42 simultaneously grips two of the substrate holders 18which now hold no substrates, and return the substrate holders 18 to theprescribed position in the stocker 24, as described above. Subsequently,the transporter 42 of the substrate holder transport device 40 grips twoof the substrate holders 18 holding substrates that have been returnedto the stocker 24 after the plating process, and transports thesubstrate holders 18 onto the loading plate 52, as described above. Thesame process is repeated.

The process is completed when all substrates have been taken out of thesubstrate holders, which have been holding substrates after the platingprocess and returned to the stocker 24, spin-dried and returned to thecassette 10. This process provides substrates W that have a plated film504 grown in the opening 502 a formed in the resist 502, as shown inFIG. 27B.

The substrate W which has been spin dried, as described above, isimmersed in a solvent, such as acetone, that is maintained at atemperature of 50-60° C., for example. In this process, the resist 502is peeled off from the surface of the substrate W, as shown in FIG. 27C.Next, an unnecessary portion of the seed layer 500 exposed after theplating process is removed, as shown in FIG. 27D, for thereby formingthe bump.

In this example, the stocker 24 for housing the substrate holders 18 ina vertical position is provided between the substrateattaching/detaching unit 20 and plating units 38. The first transporter42 of the substrate holder transport device 40 transports the substrateholders 18 between the substrate attaching/detaching unit 20 and stocker24, and the second transporter 44 of the substrate holder transportdevice 40 transports the substrate holders 18 between the stocker 24 andplating units 38, respectively. Unused substrate holders 18 are storedin the stocker 24. This is designed to improve throughput by providingsmooth transporting of the substrate holders 18 on either side of thestocker 24. However, it is of course possible to use one transporter toperform all transporting operations.

Further, a robot having a dry hand and a wet hand may be employed as thesubstrate transfer device 22. The wet hand is used only when taking outplating-processed substrates from the substrate holders 18. The dry handis used for all other operations. In principle, the wet hand is notnecessarily required since a backside of the substrate does not contactwith plating solution due to the seal of the substrate holder 18.However, by using the two hands in this manner, it is possible toprevent a possible contamination with plating solution due to poorsealing or invasion to the backside of rinse water, from contaminatingthe backside of a new substrate.

According to the substrate holder 18 of the above-described embodiment,such electrical contacts are employed as the electrical contacts 88 thathave a positioning (centering) function for the substrate W, and afunction of preventing the substrate W from sticking to the sealingportion 62 a of the inner sealing member 62 and being brought up alongwith the sealing portion 62 a when taking the substrate W after platingout of the substrate holder 18. Structure of the substrate holder 18 canbe simplified by use of such electrical contacts 88. Besides electricalcontacts, as shown in FIGS. 10A to 10C, it is also possible to providethe movable holding member 58 with leaf spring members 140 having apositioning (centering) function for the substrate W, and a function ofpreventing the substrate W from sticking to the sealing portion 62 a ofthe inner sealing member 62 and being brought up along with the sealingportion 62 a when taking the substrate W after plating out of thesubstrate holder 18. The leaf spring member 140 may be disposed, forexample, at each location between two adjacent electrical contacts 88.This operation of leaf spring members 140 is substantially the same asthat of the above-described electrical contacts 88 shown in FIGS. 5A to5C, and hence a description thereof is here omitted.

Since the substrate W is biased inwardly by an elastic force of the leafspring members 140, positioning (centering) of the substrate W relativeto the substrate holder 18 upon holding of the substrate by thesubstrate holder 18 can be effected by the leaf spring members 140.Further, by providing the movable holding member 58 with the sealingmember 62, the electrical contacts and the leaf spring members 140, andeffecting positioning of the substrate W by the leaf spring members 140,it becomes possible to make a positional relationship between thesubstrate W, the sealing member 62 and the electrical contacts alwaysconstant when the substrate W is held by the substrate holder 18.

In this regard, a precise centering can be effected with difficulty onlythrough engagement between the above-described tapered portions 82 a,90. This is because a clearance, if small, is necessary between the twotapered portions 82 a, 90 in order to facilitate the engagementtherebetween. Accordingly, the center of the substrate inevitablydeviates from the center of the movable holding member 58 by theclearance. In view of this, the movable holding member 58 is providedwith the plurality of leaf spring members 140 so that they make elasticcontact with the peripheral edge of the substrate W and evenly apply apressing force acting to move the substrate W toward the center of themovable member 58. Accordingly, when the movable holding member 58engages the fixed holding member 54, the substrate W is shifted so thatthe center of the substrate can coincide exactly with the center of themovable holding member 58.

Though in the above-described embodiment each leaf spring member 140 iscomprised of a single plate formed in the shape of a leaf spring, theleaf spring member 140 may be comprised of a leaf spring-shaped laminateof two or more plates, for example, a laminated leaf spring 124consisting of plates 122 a, 122 b shown in FIG. 11.

Such leaf spring members 140 (laminated leaf springs 124) can secure along stroke without plastic deformation and can be set in a considerablysmall space. Positioning (centering) of the substrate W with respect tothe substrate holder 18 can be effected by the leaf spring members 140(laminated leaf springs 124) in the course of holding the substrate W bythe substrate holder 18. Further, when the substrate W after plating istaken out the substrate holder 18, the laminated leaf springs 124 canprevent the substrate W from sticking to the sealing portion 62 a of theinner sealing member 62 and being brought up along with the innersealing member 62.

Further, as shown in FIGS. 12 through 14, it is possible to use as theinner sealing member 62 a multi-seal structure 128 comprising tworing-shaped sealing portions 126 a, 126 b on both sides in a widthdirection, and partition sealing portions 126 c extending in the widthdirection and provided at certain locations along a circumferentialdirection. By sealing a peripheral portion of the substrate W with thesealing member 62 comprised of the multi-seal structure 128, a sealingwidth is substantially widened, so that a more complete sealing can beattained even when centering of the substrate is not perfect. Further,by sealing certain portions along a circumferential direction of theinner sealing member 62 with the partition sealing portions 126 c in thewidth direction, it becomes possible to maintain a sealing ability ofthe inner sealing member 62 even when it is damaged.

In particular, as shown in FIGS. 13A and 13B, due to a deviation incentering of the substrate W, there may be a case where the sealingportion 126 b, positioned on an inner side of the multi-seal structure128, crosses over a resist line R having a step on a surface of thesubstrate (FIG. 13A), or a case where the sealing portion 126 a,positioned on an outer side of the multi-seal structure 128, crossesover the resist line R (FIG. 13B). Even in such cases, at least one ofthe sealing portions 126 a, 126 b, not crossing over the resist line R,constitutes a sealing line, as shown by shaded lines in FIGS. 13A, 13B,whereby sealing is ensured if a liquid leak occurs at a crossingportion. Further, if the sealing portions 126 a, 126 b are damaged, forexample at sites X₁ and X₂ close to each other and on both sides of thepartition sealing portion 126 c as shown in FIG. 13B, a sealing abilitycan be maintained with the partition sealing portion 126 c positionedbetween damaged sites X₁ and X₂.

FIG. 15 shows a substrate holder according to another embodiment of thepresent invention. The substrate holder of this embodiment differs fromthe above-described substrate holder in that on the movable holdingmember 58 side surface of the fixed holder member 54 is provided a pairof conducting lines (conductors) 130 for detecting a liquid leak which,when a plating solution leaks to a back surface side of the substrate Wheld by the movable holding member 58 and the fixed holding member 54,short-circuits via this leaked plating solution. The pair of conductinglines 130 extends continuously and circumferentially on a surface of thefixed holding member 54 such that it extends over almost an entireperipheral back surface of the substrate W. Further, the pair ofconducting line 130 is open at one end, and at the other end isconnected to an electric resistance measuring device 132. Otherconstruction is the same as the above-described substrate holder.

According to this embodiment, occurrence of a liquid leak can bedetected quickly and securely by measuring electric resistance betweenthe pair of conducting lines 130 by the electric resistance measuringdevice 132. Thus, the pair of conducting lines 130 is open at one end,and therefore an electric current usually does not flow. However, when aleak of plating solution occurs, the plating solution, which is aconductor, short-circuits the pair of conducting lines 130 whereby anelectric current flows through the conducting lines 130. That is, theplating solution behaves like a resistance R, as illustrated byimaginary lines in FIG. 15, which short-circuits the pair of conductinglines 130. Accordingly, measurement of the electric resistance via theelectric current can detect leakage of plating solution.

According to this embodiment, the pair of conducting lines (conductors)is disposed such that it extends continuously over the entire peripheralback surface of the substrate. By thus disposing the pair of conductinglines right inside the peripheral sealing portion of the substrate, itbecomes possible to immediately detect a leak wherever the leak occurs.Alternatively, unlike this embodiment, it is also possible to provide apair of conducting lines at any location, for example, a location wherea leaked liquid is likely to collect, or provide a plurality of pairs ofconducting lines in parallel.

For instance, as shown in FIG. 16, a pair of conductive plates(conductors) 142, connected to a pair of electrodes respectively, may bedisposed opposite to each other at a predetermined spacing at a bottomportion of the fixed holding member 54 where plating solutionaccumulates in case leakage of the solution occurs. An electric currentflows between the conductive plates 142 via the plating solution whenthe solution accumulates at the bottom portion of the fixed holdingmember 54 after occurrence of this leak. According to this embodiment,by disposing the conductive plates 142 at such a local location as thebottom portion of the fixed holding member 54, a liquid leak over anentire area of the substrate holder 18 can be detected.

As described hereinabove, according to the plating apparatus of thepresent invention, by simply setting a cassette housing substrates onthe cassette table and activating the apparatus, electroplatingemploying a dipping method can be performed fully automatically to forma plated metal film suited for formation of bumps.

Further, according to the present invention, a suction pad forattracting the back surface of the substrate, held by the fixed holdingmember and the movable holding member, may be mounted to the fixedholding member. Since the back surface of the substrate is keptattracted to the suction pad, when the movable holding member is movedafter plating to release holding of the substrate and take the substrateout of the substrate holder, the substrate can be prevented fromsticking to the inner sealing member and moving along with the innersealing member. The substrate can thus be taken out of the substrateholder in a stable manner.

Further, since the inner sealing member for sealing a peripheral portionof the substrate may be integrally mounted on a holding member forholding the inner sealing member, when the movable holding member ismoved after plating to release holding of the substrate and thesubstrate is taken out of the substrate holder, the sealing portion ofthe inner sealing member can be prevented from adhering to thesubstrate, and hence the inner sealing member can be prevented frombeing torn off from the holding member. Releasability of the innersealing member from the substrate can thus be improved.

Further, the outer sealing member for sealing between the movableholding member and the fixed holding member may be one that has aW-shaped cross-section, which easily collapses when pressed in the widthdirection and recovers by elastic force when a pressing force isreleased. Use of such an outer sealing member can facilitate itsinsertion into the seal groove, e.g. in a dovetail shape, and prevent itfrom falling from the seal groove.

Further, a leaf spring member may be mounted on the movable holdingmember so that the substrate is biased toward the fixed moving memberwhen holding of the substrate between the moveable holding member andthe fixed holding member is released. Accordingly, when the movablemember is moved after plating to release the holding of the substrateand take the substrate out of the substrate holder, movement of thesubstrate is restricted and the inner sealing member mounted on themovable holding member is detached from the substrate, whereby thesubstrate can be prevented from sticking to the inner sealing member andmoving along with the inner sealing member.

Furthermore, the movable holding member may be provided with at leastone pair of conductors for detecting a liquid leak which, when a platingsolution leaks to a back surface side of a substrate held by the movableholding member and the fixed holding member, short-circuits via thisleaked plating solution.

This enables an immediate detection of occurrence of a liquid leak andmakes it possible to deal with the liquid leak promptly, therebypreventing the liquid leak from adversely affecting the apparatus andquality of plating.

FIGS. 17 through 22F show a substrate holder according to still anotherembodiment of the present invention. This substrate holder has a fixedholding member 154 made of, for example, a vinyl chloride resin in theform of a rectangular flat plate, and a movable holding member 158mounted openably and closably via a hinge 156 on the fixed holdingmember 154. While the movable holding member 158 is shown as beingopenably and closably mounted on the fixed holding member 154 by thehinge 156 in present embodiment, the movable holding member 158 may bedisposed in a position facing the fixed holding member 154 and may bemoved forward to the fixed holding member 154 so as to be opened andclosed with respect thereto.

The movable holding member 158 has a base portion 158 a and aring-shaped support portion 158 b, and is made of, for example, a vinylchloride resin for better slippage against a below-described press ring162. A ring-shaped sealing member (seal ring) 160 that is of asubstantially channel-shaped transverse cross section having two lips,one being longer than the other, is mounted on a surface of the supportportion 158 b which faces the fixed holding member 154, with thering-shaped sealing member 160 being open toward the fixed holdingmember 154.

The press ring 162 is rotatably supported on a surface of the supportportion 158 b on a far side from the fixed holding member 154, and slideplates 164 are jointed to outer circumferential surfaces of the pressring 162. The press ring 162 is made of, for example, titanium that ishighly resistant to corrosion in oxidizing environments and hassufficient rigidity.

Inverted L-shaped clampers 170, each having an inward protrusion, arevertically mounted on the fixed holding member 154 at circumferentiallyequal spaced intervals in positions laterally outward of the slideplates 164. Surfaces of the slide plates 164, and lower surfaces of theinward protrusions of the clampers 170, which are positioned in coveringrelation to the surfaces of the slide plates 164, are tapered so as tobe slanted oppositely to each other in a rotational direction.Projections 173, which comprise rotary pins threaded into the press ring162, for example, are mounted on a surface of the press ring 162respectively in a plurality of locations (e.g., four locations) along acircumferential direction of the press ring 162. The projections 173 areengaged by a rotating mechanism (locking/unlocking mechanism) forrotating the press ring 162 in unison with the slide plates 164.

When the movable holding member 158 is open, substrate W is insertedinto a center of the fixed holding member 154. After the movable holdingmember 158 is closed about the hinge 156, the press ring 162 is turnedclockwise to cause the slide plates 164 to slide into the protrusions ofthe clampers 170, thereby fastening and locking the fixed holding member154 and the movable holding member 158 to each other through theirtapered surfaces. By turning the press ring 162 counterclockwise, theslide plates 164 are removed from the protrusions of the L-shapedclampers 170, thereby unlocking the fixed holding member 154 and themovable holding member 158 from each other. When the movable holdingmember 158 is locked, a shorter lip 160 a on an inner circumferentialsurface of the sealing member 160 is in pressure contact with a surfaceof the substrate W, and a longer lip 160 b on an outer circumferentialsurface of the sealing member 160 is in pressure contact with a surfaceof the fixed holding member 154, respectively. The sealing member 160 isthus uniformly pressed against the substrate W and the fixed holdingmember 154 to seal the surface of the substrate W and the surface of thefixed holding member 154 reliably.

A ridge 182 is mounted centrally on and projects from the fixed holdingmember 154 in a ring shape matching a size of the substrate W. The ridge182 provides a support surface 180 for abutting a peripheral edge of thesubstrate W to support the substrate W thereon. The ridge 182 has aplurality of recesses 184 defined therein at predetermined positionsalong a circumferential direction thereof.

As shown in FIGS. 17, 20A and 20B, a plurality of (eight in theillustrated embodiment) conductors (electrical contacts) 188 aredisposed respectively in the recesses 184 and connected to respectivewires extending from external contacts on a below-described hand 198.When the substrate W is placed on the support surface 180 of the fixedholding member 154, the conductors 188 have their springy ends exposedon the surface of the fixed holding member 154 laterally of thesubstrate W.

A support body 190 is mounted in an inner space of the sealing member160 which is defined between the lips 160 a, 160 b. Electrical contacts192 have respective legs 192 a fixed to the support body 190 atpositions confronting the conductors 188. Each electrical contact 192 isformed in a leaf springs shape. Specifically, the electrical contacts192 have contact ends 192 b projecting inwardly as leaf springs that caneasily flex under their own resiliency.

As shown in FIG. 26A, the contact ends 192 b are arranged as a pluralityof parallel rectangular strips projecting equal lengths toward thesubstrate W. The electrical contacts 192 are attached to the supportbody 190 such that a line interconnecting tips of the contact ends(strips) 192 b is slightly inclined relative to a tangential directionof the substrate W. As shown in FIG. 26A, therefore, the tips of thecontact ends (strips) 192 b are held in contact with a contact area A,shown hatched, on the surface of the substrate W in respective differentpositions in a transverse direction of the contact area A. Even if thesubstrate W suffers a slight positioning error, at least some of thetips of the contact ends (strips) 192 b are brought into contact withthe substrate W in the contact area A thereof.

Alternatively, as shown in FIG. 26B, a plurality of elongated electricalcontacts 192 may be disposed at predetermined spaced intervals across adiametrical direction of the substrate W, and may have respectivecontact ends 192 b having respective tips held in contact with a contactarea A, shown hatched, on the surface of the substrate W in respectivepositions along a circumferential direction of the contact area A. Withthis arrangement, even if dirt or the like is attached to the contactends 192 b of some of the electrical contacts 192, the other electricalcontacts 192 are kept electrically connected to the substrate W.

Further alternatively, as shown in FIG. 26C, the electrical contacts 192may be attached to the support body 190 such that a line interconnectingthe tips of the contact ends (strips) 192 b, which are arranged as aplurality of parallel rectangular strips projecting equal lengths towardthe substrate W, extends parallel to a tangential direction of thesubstrate W. Still further alternatively, as shown in FIG. 26D, thecontact ends (strips) 192 b, which are arranged as a plurality ofparallel rectangular strips, may project respective different lengthstoward the substrate W. With these modifications, the tips of thecontact ends (strips) 192 b are held in contact with the contact area A,shown hatched, on the surface of the substrate W in respective differentpositions in the transverse direction of the contact area A. Even if thesubstrate W suffers a slight positioning error, at least some of thetips of the contact ends (strips) 192 b are brought into contact withthe substrate W in the contact area A thereof.

When the movable holding member 158 is locked to hold the substrate Wwith the fixed holding member 154 and the movable holding member 158, asshown in FIG. 20B, exposed portions of the conductors 188 areresiliently held in contact with and electrically connected to lowersurfaces of the legs 192 a of the electrical contacts 192 underresiliency of the exposed portions of the conductors 188 in a positionsealed by the sealing member 160, i.e., a region sandwiched between thelips 160 a, 160 b of the sealing member 160. The substrate W is thusresiliently held in contact with the tips of the contact ends 192 b ofthe electrical contacts 192 under resiliency of the contact ends 192 b.In this manner, while the substrate W is being sealed by the sealingmember 160 and held by the substrate holder, the substrate W can besupplied with electric energy through the electrical contacts 192.

Since the electrical contacts 192 are in the form of leaf springs tohold the tips of the contact ends 192 b of the electrical contacts 192in contact with the substrate W under resiliency of the electricalcontacts 192, contact failures are reduced, and the electrical contacts192 are held in contact with the substrate W in an outer circumferentialregion thereof, thus increasing an area of the substrate W that caneffectively be used as a pattern formation area.

At least the surfaces of the conductors 188 which are to be held againstthe electrical contacts 192 may preferably be plated with gold orplatinum.

As shown in FIGS. 21A and 21B, the ridge 182 of the fixed holding member154 partly has a tapered portion 182 with a steeple-shaped taperedsurface, and an inner circumferential surface of the support body 190has a tapered portion 190 a which complementarily faces the taperedportion 182 a. When the fixed holding member 154 and the movable holdingmember 158 hold the substrate W, the tapered portions 182 a, 190 aengage each other to position the fixed holding member 154 and themovable holding member 158 in central alignment with each other.Specifically, as shown in FIG. 21B, when the fixed holding member 154and the movable holding member 158 hold the substrate W, the taperedportions 182 a, 190 a guide each other, thereby positioning the movableholding member 158 with respect to the fixed holding member 154 orpositioning the fixed holding member 154 with respect to the movableholding member 158.

Because of the tapered portions 182 a, 190 a of the ridge 182 of thefixed holding member 154 and the support body 190 of the movable holdingmember 158, even if the fixed holding member 154 and the movable holdingmember 158 are not accurately positionally aligned with respect to eachother when they are spaced from each other, they can automatically bepositioned aligned with each other by the tapered portions 182 a, 190 awhile the fixed holding member 154 and the movable holding member 158are in a process of holding the substrate W.

The tapered portion 190 a of the support body 190 of the movable holdingmember 158 serves to guide an outermost circumferential edge of thesubstrate W supported on the support surface 180 of the ridge 182 of thefixed holding member 154 to position the substrate W, when the fixedholding member 154 and the movable holding member 158 hold the substrateW. Specifically, as shown in FIG. 21B, when the outer circumferentialportion of the substrate W projects outwardly from the support surface180 of the ridge 182, the outermost circumferential edge of thesubstrate W contacts the tapered portion 190 a, thereby positioning(centering) the substrate W with respect to the substrate holder andhence the sealing member 160.

Thus, while the fixed holding member 154 and the movable holding member158 are in a process of holding the substrate W, they are centrallypositioned with respect to each other, and at the same time the taperedportion 190 a of the support body 190 of the movable holding member 158positions (centers) the substrate W with respect to the substrateholder.

Furthermore, as shown in FIGS. 22A to 22F, a plurality of grooves 194are defined in the surface of the fixed holding member 154 at positions,along the circumferential direction, which face the sealing member 160.Leaf spring members 196 which extend upwardly are disposed respectivelyin the grooves 194 with their lower ends fixed in position. The leafspring members 196 are made springy with their lower ends being fixedand upper ends being free. The leaf spring members 196 have springyextensions (free end portions) 196 a, which extend outwardly obliquelyin an upward direction, and arcuate engaging portions 196 b on tip endsof the extensions 196 a.

The support body 190 of the movable holding member 158 has, on its innercircumferential surfaces facing the leaf spring members 196, guidesurfaces each comprising a tapered surface 190 c slanted inwardly in theupward direction and a vertical surface 190 d extending verticallycontiguously to the tapered surface 190 c.

As shown in FIGS. 22A and 22B, as the movable holding member 158 islowered, the engaging portion 196 b on the tip of each leaf springmember 196 is engaged and guided by the tapered surface 190 c, therebycausing the leaf spring member 196 to be bent inwardly. Upon furtherdownward movement of the movable holding member 158, as shown in FIG.22C, the engaging portion 196 b on the tip of the leaf spring member 196is positioned inwardly of the vertical surface 190 d, thereby causingthe extension 196 a to extend vertically, whereupon the leaf springmember 196 will not be bent further inwardly. The engaging portion 196 bof the leaf spring member 196 is now positioned over the outercircumferential edge of the substrate W which is supported on thesupport surface 180 of the fixed holding member 154. Continued descentof the movable holding member 158 presses the shorter lip 160 a on theinner circumferential side of the sealing member 160 against the surfaceof the substrate W and also presses the longer lip 160 b on the outercircumferential side of the sealing member 160 against the surface ofthe fixed holding member 154, respectively, thus uniformly pressing thesealing member 160 to seal the substrate W and the fixed holding member154 securely. The substrate W is then processed, e.g., plated.

After a series of processing of the substrate W is finished, the movableholding member 158 is elevated to remove the substrate W which has beenheld by the substrate holder. At this time, as shown in FIG. 22D, sincethe engaging portion 196 b on the tip of the leaf spring member 196 ispositioned inwardly of the vertical surface 190 d, the leaf springmember 196 is limited in its movement. Consequently, even if thesubstrate W is sticking to the sealing member 160, the engaging portion196 b on the tip of the leaf spring member 196 engages an upper surfaceof an outer circumferential surface of the substrate W, therebypreventing the substrate W from ascending. The sealing member 160, themovable holding member 158, and the support body 190 are lifted, therebyforcing the substrate W off the sealing member 160. When the movableholding member 158 is further elevated, as shown in FIG. 22E, theengaging portion 196 b on the tip of the leaf spring member 196 spreadsprogressively outwardly under its own resiliency while in abutmentagainst the tapered surface 190 c of the support body 190, until itreturns to its original position as shown in FIG. 22F. At this time, theengaging portion 196 b of the leaf spring member 196 is positionedoutwardly of the outer circumferential portion of the substrate W whichis supported on the support surface 180 of the fixed holding member 154.Therefore, a processed substrate W is not prevented from being taken outof the substrate holder by the leaf spring member 196, and a substrateto be processed is not prevented by the leaf spring member 196 frombeing inserted in place.

Accordingly, after the substrate W has been plated, when the movableholding member 158 is moved to release the substrate W and the substrateW is taken out of the substrate holder, the substrate W is preventedfrom sticking to and moving with the sealing member 160. Since the freeend of the leaf spring member 196 is positioned outwardly of the outercircumferential portion of the substrate W when the movable holdingmember 158 is thus moved, the substrate W is not prevented from beingtaken out of the substrate holder.

As described above, the sealing member 160 has the lips 160 a, 160 b forcontacting the circumferential edge of the substrate W and the surfaceof the fixed holding member 158, respectively, when the substrate W isheld by the fixed holding member 158 and the movable holding member 154,and the sealing member 160 is held integrally by the support body 190which is disposed between the lips 160 a, 160 b. Specifically, thesealing member 160 has a flat portion joining the lips 160 a, 160 b andsandwiched between the support portion 158 b of the movable holdingmember 158 and the support body 190. The sealing member 160 is fixed inposition by fastening the support portion 158 b of the movable holdingmember 158 and the support body 190 with bolts 91 (see FIGS. 21A and21B).

Further, on the upper surface of the sealing member 160 is integrallyprovided a pair of radially spaced sealing portions 193 which makescontact with the lower surface of the support portion 158 a of themovable holding member 158. The bolts 191 are disposed between the pairof sealing portions 193, and the sealing member 160 is fixed between thesupport 190 and the support portion 158 a by fastening the bolts 194 tosquash the sealing portions 193. This prevents leakage of water from aninterstice between the support portion 158 a and the sealing member 160,shown by the arrow in FIG. 21A, even when a force is applied to the lipportions 160 a, 160 b of the sealing member 160 in such a direction(downward direction) that it forces the lip portions 160 a, 160 b awayfrom the support portion 158 b.

Inasmuch as the sealing member 160 is held integrally on the supportbody 190, when the movable holding member 158 is moved to release thesubstrate W and the substrate W is taken out of the substrate holderafter the substrate W has been plated, the lip (seal) 160 a of thesealing member 160 is prevented from sticking to the substrate W andbeing turned up from the support portion 158 b of the fixed holdingmember 158, thereby improving peelability between the sealing member 160and the substrate W.

The movable holding member 158 is opened and closed by a cylinder (notshown) and weight of the movable holding member 158 per se.Specifically, the fixed holding member 154 has a through-hole 154 a, asshown in FIG. 19, and a cylinder is disposed in a position whichconfronts the through-hole 154 a of the substrate holder placed on aloading plate 152. When the piston rod of the cylinder is extended apusher rod is caused to lift the base portion 158 a of the movableholding member 158 through the through-hole 154 a, thereby opening themovable holding member 158. When the piston rod is retracted, themovable holding member 158 is closed under its own weight.

In the present embodiment, the press ring 162 is rotated to lock andunlock the movable holding member 158. A locking/unlocking mechanism forlocking and unlocking the movable holding member 158 is mounted on aceiling side. The locking/unlocking mechanism has gripping membersdisposed in respective positions aligned with the projections 173 of thepress ring 162 of a centrally positioned substrate holder placed on theloading plate 152. The locking/unlocking mechanism is arranged to rotatethe press ring 162 when the gripping members are turned about an axis ofthe press ring 162 with the loading plate 152 being lifted and theprojections 173 being gripped by the gripping members. There is a singlelocking/unlocking mechanism being used, and after the locking/unlockingmechanism locks (or unlocks) one of two substrate holders placed on theloading plate 152, the loading plate 152 is slid horizontally, and thelocking/unlocking mechanism locks (or unlocks) the other substrateholder.

The substrate holder has a sensor for inspecting a state of contactbetween the substrate W and the contacts when the substrate W is heldwith the substrate holder. A signal from the sensor is supplied to acontroller (not shown).

A pair of substantially T-shaped hands 198 is jointed to an end of thefixed holding member 154 of the substrate holder. The hands 198 serve assupports at a time of transporting the substrate holder, and suspendingand supporting the substrate holder.

In the above embodiment, the tips of the contact ends 192 b of theelectrical contacts 192 are resiliently held in contact with the surfaceof the substrate W that is supported on the support surface 180 of thefixed holding member 154. However, as shown in FIGS. 23A and 23B, whenthe fixed holding member 154 and the movable holding member 158 hold thesubstrate W, the contact ends 192 b of the electrical contacts 192 mayresiliently contact the outer circumferential surface of the substrate Wthat is supported on the support surface 180 of the fixed holding member154, so that the electrical contacts 192 serve both as contacts and leafspring members for positioning the substrate W.

When the substrate holder holds the substrate W, since the substrate Wis biased inwardly under resiliency of the electrical contacts 192 inthe form of leaf spring members, the electrical contacts (leaf springmembers) 192 can effect positioning (centering) of the substrate W withrespect to the substrate holder. Because the sealing member 160 and theelectrical contacts 192 are provided on the movable holding member 158and the substrate W is positioned with respect to the substrate holderby the electrical contacts 192, when the substrate W is held by thesubstrate holder, the substrate W, the sealing member 160, and theelectrical contacts 192 are always kept in constant positionalrelationship relative to each other.

As shown in FIGS. 24A to 24F, electrical contacts/leaf spring members200 which serve both as the above-described electrical contacts 192 andthe above-described leaf spring members 196 may be disposed in recesses202 defined in the surface of the fixed holding member 154 atpredetermined positions along the circumferential directions in facingrelation to the sealing member 160.

The electrical contacts/leaf spring members 200 differ in operation fromthe above-described leaf spring members 196 in that, as shown in FIG.24C, when an engaging portion 200 b on a tip of each electricalcontacts/leaf spring member 200 is positioned inwardly of a verticalsurface 190 d of the support body 190, with an extension 200 a extendingvertically, thereby preventing the electrical contacts/leaf springmember 200 from being bent further, the electrical contacts/leaf springmember 200 is held in contact with the outer circumferential portion ofthe substrate W that is supported on the support surface 180 of thefixed holding member 154 to supply the substrate W with electric energy.When the substrate W is to be released, the engaging portion 200 b onthe tip of the electrical contacts/leaf spring member 200 iscontinuously held in abutment against the outer circumferential portionof the substrate W, whereby only the sealing member 160 is lifted toforce the substrate W off the sealing member 160. Other operationaldetails of the electrical contacts/leaf spring members 200 are the sameas the leaf spring members 196 shown in FIGS. 22A to 22F.

With the electrical contacts/leaf spring members 200 which serve both asthe electrical contacts 192 and the leaf spring members 196, it is notnecessary to provide dedicated leaf spring members for a sole purpose ofseparating the substrate W from the sealing member when the substrateholder releases the substrate W, and hence the substrate holder can besimplified in terms of structure.

Although not shown, when the fixed holding member 154 and the movableholding member 158 hold the substrate W, the engaging portion 200 b onthe tip of the electrical contacts/leaf spring member 200 may beresiliently held against the outer circumferential surface of thesubstrate W that is supported on the support surface 180 of the fixedholding member 154, and when the substrate W is held by the substrateholder, the substrate W may be biased inwardly under resiliency of theelectrical contacts/leaf spring member 200, so that the substrate W maybe positioned (centered) with respect to the substrate holder by theelectrical contacts/leaf spring member 200.

Furthermore, as shown in FIGS. 25A and 25B, a leaf spring member 210which is springy to be resiliently held against the outercircumferential end of the substrate W to position the substrate W whenthe fixed holding member 154 and the movable holding member 158 hold thesubstrate W, may be supported on the support body 190 separately fromthe electrical contact 192. The leaf spring member 210 may be disposedin a position between two adjacent electrical contacts 192 shown inFIGS. 20A and 20B, for example.

In a process of holding the substrate W with the substrate holder, thesubstrate W is biased inwardly under resiliency of the leaf springmember 210, and hence positioned (centered) with respect to thesubstrate holder by the leaf spring member 210. Since the sealing member160, the electrical contacts 192, and the leaf spring members 210 forpositioning the substrate are mounted on the movable holding member 158,and the substrate W is positioned by the leaf spring members 210, whenthe substrate W is held by the substrate holder, the substrate W, thesealing member 160, and the electrical contacts 192 are always kept inconstant positional relationship relative to each other by the leafspring members 210.

As described above, the plating apparatus according to the presentinvention performs an electroplating process of a dipping type fullyautomatically for automatically forming a plated film of metal suitablefor bumps, or the like on a surface of a substrate by setting a cassettehousing substrates on a cassette table and starting to operate theplating apparatus.

According to the present invention, as described above, since theelectrical contacts are constructed as a form of leaf springs andbrought into contact with the substrate under their own resiliency,contact failures are reduced, and the electrical contacts are held incontact with the substrate in an outer circumferential region thereof,thus increasing an area of the substrate that can effectively be used asa pattern formation area.

The fixed holding member and the movable holding member have respectivetapered portions for engaging each other, thereby positioning themcentrally with respect to each other when they hold a substrate.Therefore, in a process of holding the substrate with the fixed holdingmember and the movable holding member, the fixed holding member and themovable holding member are automatically positioned in central alignmentwith each other by the tapered portions that engage each other.

Furthermore, the leaf spring member is disposed in a region of the fixedholding member which is sealed by the sealing member when the substrateis held. The leaf spring member has its free end positioned inwardly ofthe outer circumferential edge of the substrate when the substrate isheld with the fixed holding member and the movable holding member, andpositioned outwardly of the outer circumferential edge of the substratewhen the substrate is released from the fixed holding member and themovable holding member. Therefore, after the substrate has been plated,when the movable holding member is moved to release the substrate andthe substrate is taken out of the substrate holder, the substrate isprevented from sticking to and moving with the sealing member, andpossibly from being dislodged out of position.

Although certain preferred embodiments of the present invention havebeen shown and described in detail, it should be understood that variouschanges and modifications may be made therein without departing from thescope of the appended claims.

INDUSTRIAL APPLICABILITY

The present invention relates to a substrate holder for use in a platingapparatus for forming a plated film in fine interconnect trenches orholes, or resist openings provided in a surface of a semiconductorwafer, or for forming bumps (protruding electrodes), which are to beelectrically connected to electrodes, or the like, of a package, on asurface of a semiconductor wafer.

1. A substrate holder, comprising: a fixed holding member and a movableholding member for holding a substrate therebetween; and a sealingmember for sealing an outer circumferential end of the substrate whenthe substrate is held between said movable holding member and said fixedholding member, wherein said fixed holding member and said movableholding member have respective tapered portions for engaging each otherand positioning said fixed holding member and said movable holdingmember in central alignment with each other when the substrate is heldbetween said movable holding member and said fixed holding member, andwherein said tapered portion of said movable holding member is adaptedto guide an outer circumferential edge of the substrate to position thesubstrate when the substrate is held between said movable holding memberand said fixed holding member; and wherein said movable holding memberhas a plurality of leaf spring members configured such that each of saidleaf spring members makes elastic contact with the outer circumferentialedge of the substrate when the substrate is held between said movableholding member and said fixed holding member so that a center of thesubstrate coincides with a center of said movable holding member.
 2. Thesubstrate holder according to claim 1, wherein said fixed holding memberhas a conductor, and one of said leaf spring members of said movableholding member forms an electrical contact for being electricallyconnected to said conductor and for making contact with a peripheralportion of the substrate to supply the substrate with electric energywhen the substrate is held between said movable holding member and saidfixed holding member.
 3. The substrate holder according to claim 2,wherein said electrical contact is adapted to make an elastic contactwith the outer circumferential edge of the substrate when the substrateis held between said movable holding member and said fixed holdingmember.
 4. The substrate holder according to claim 1, wherein saidmovable holding member and said fixed holding member are coupled by ahinge.
 5. The substrate holder according to claim 1, wherein said fixedholding member has a support surface for holding the substrate thereon.6. The substrate holder according to claim 1, wherein said movableholding member has an opening portion configured to expose a surface tobe plated of the substrate.
 7. The substrate holder according to claim1, further comprising a press ring for locking and unlocking saidmovable holding member to said fixed holding member so as to hold thesubstrate therebetween.